By Gail Cochrane

Liberty Wildlife Volunteer

The rains of winter have brought about a brilliant flush of wildflowers, and in the coming weeks clouds of blooms will enfold our native trees. The blossoming and fruiting of annual wildflowers and legume trees like ironwoods, Palo Verdes and acacias feed desert birds and mammals and attract insects that sustain baby birds. This is the season when pollinators such as native bees become our most important players.

There are around 1000 different species of bees in the Sonoran Desert. Specifically, the area around Tucson has perhaps more different kinds of native bees than anywhere else in the world.

These native bees come in many shapes and sizes and with many different habits. The world’s smallest bee, Perdita minima lives here, growing to just 2 millimeters in size.  You have probably noticed Carpenter bees from the genus Xylocopa bumbling around flowers in your yard. These gentle bees are 1 ½ inches long.

Most desert bees are solitary rather than colony bees. Herbivores, they feed on pollen, nectar and plant oils. Some species live in underground burrows, some hollow out the pithy stems of plants, and others live in tunnels abandoned by wood boring beetles. Many solitary bees secrete a waxy substance to line their burrows, capturing humidity inside and keeping fungi out.

Plants depend on bees and other pollinators, allowing for fruits and seeds that create new generations of their species. Birds and mammals eat the fleshy berries and fruits promised by pollination. Bee tunnels aerate the soil at the base of plants and direct rainwater to deep underground roots. Even bee waste (poop) is helpful, as it adds nutrients to the soil. Further enriching the desert biome, some bees become food for lizards, mammals, insects and spiders.

Unlike colonies of honey bees that live in hives, solitary bees raise their young in individual brood cells created in a variety of ways. Mason bees use water and mud to make adobe nests. Leaf cutter bees cut circular pieces of leaves to make cell walls. Other bees collect pebbles, plant hairs and floral resins for brood cell building materials.

As you walk among the flowering trees of the desert this spring, take time to listen to the resonant buzz of bees. Stop and admire the small, industrious workers humming among the blooms. Rather than insects to be afraid of, these critters are incredibly important to our web of life –  pollinating 80% of our native flowering plants.

Captions:

Cactus Bee pollinates prickly pear, saguaro and cholla cacti. Photo by Jengod – Own work, CC BY-SA 4.0

Perdita minima on the head of a Carpenter Bee.  Photo by Stephen Buchmann

Mexican Poppies and Scorpion Weeds on South Mountain.  Photo by G Cochrane